fix: Allow copy/paste in location bar text input

[JayDoubleu]

Summary

• Allow Ctrl+C/V/X keyboard shortcuts to work in the location bar text input (previously triggered file copy/cut/paste operations instead)
• Add right-click context menu with "Copy path" option for the location bar text input

Changes

1. Keyboard shortcuts fix: Skip file Copy/Cut/Paste key bindings when the location bar is being edited, allowing the text input widget to handle clipboard operations
2. Context menu: Add a right-click "Copy path" menu option that copies the full path to clipboard

Fixes #1505

Test plan

• Open cosmic-files and press Ctrl+L to edit the location bar
• Select text and press Ctrl+C - should copy selected text (not trigger file copy)
• Press Ctrl+V - should paste clipboard content into the text input
• Right-click on the location bar text input - should show "Copy path" menu
• Click "Copy path" - should copy the full path to clipboard

🤖 Generated with Claude Code

[iamkartiknayak]

Cut, Copy, and Paste seem to be working as expected on the latest master branch.

[iamkartiknayak]

Just tested this out

The newly implemented context menu cannot be dismissed when clicked elsewhere. Additionally, if the address bar is out of focus, it gets hidden and is shown again when the address bar is focused in edit mode. Context menu stays active indefinitely.